Support is requested for continuation of the Carcinogenesis Training Program at the University of California, Irvine. This program, administered by the UCI Cancer Research Institute, is entering its 25th year and is a broad-based training program in basic cancer- related research, encompassing faculty from the School of Biological Sciences and from basic and clinical departments in the College of Medicine. There are thirty-three training faculty, and a phased shift from eight predoctoral/four postdoctoral positions to eight postdoctoral/four predoctoral is requested. Thirty faculty have funded research grants that meet the NCI referral guidelines. Faculty research concentrations are in cell transformation and carcinogenesis; growth factors and cell signaling; cancer genetics; and experimental therapeutics. Predoctoral students are recruited through the joint graduate program in Molecular Biology, Genetics and Biochemistry. Predoctorals are typically supported for three years, and postdoctorals for two years. Trainees typically take research positions in academia, research institutions, or industry following their training. Features of this training program include (in addition to laboratory research) training grant courses ("Clinical Cancer for Basic Scientists," "Cancer Biology parts A and B"), a yearly Training Program retreat, an extensive series of national meetings, and regular multidisciplinary retreats. The UCI Chao Family Comprehensive Cancer Center (of which the Cancer Research Institute is the basic science arm) is an NCI-designated comprehensive cancer center. This enhances the possibilities for translational research.